1. Field of the Invention
The present invention relates to a message substitution response system which responds, in a network including equipment noncompliant to topology management protocol, to a discovery message or a topology search message in lieu of the noncompliant equipment.
2. Description of the Related Art
With the recent promulgation of home network, such environments that every equipment in a residence is connected to the network have been becoming common. In order to utilize the network, although it is necessary to grasp equipment being connected to the network and their relation of connection (topology), this is not easy task for users without expert knowledge.
As a technology for presenting users a topology of home network, topology management technology LLTD (Link Layer Topology Discovery) developed by Microsoft Corporation is known. With LLTD, various messages are exchanged between “mapper” that collects topology information and executes topology drawing, and LLTD compliant equipment being connected to the network and are referred to as “responder”.
For topology drawing, first, a mapper transmits a Discover message in the network in the form of broadcast frame. A responder which received this Discover message registers own MAC address to a Hello message and transmits it in the form of broadcast frame. As a result, each of LLTD compliant equipment on the network can now know MAC address of all the LLTD compliant equipment.
Second, a topology search message for investigating a relation of connection of the both among each of LLTD compliant equipment is transmitted and received in the form of unicast frame, and each of compliant equipment stores receiving records of the topology search message. Following this, the mapper collects receiving records of the topology search message from each responder, recognizes a network topology, and visualizes it for displaying and outputting.
As for the technology of displaying network topology, for example, Patent Documents 1 and 2 are known.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-285757    [Patent Document 2] Japanese Patent Application Laid-Open No. 09-186716
In order to draw topology utilizing LLTD and existing network topology management technology, all the equipment on the network should be in compliance with a specific topology management protocol. However, to effect all the network equipment located in the residence to be in compliance with the specific topology management protocol is difficult from viewpoints of resource and costs of the equipment.